Year: 2002
Type: article
Abstract: A range of monodomain nematic liquid-crystal elastomers containing differing proportions of photoisomerizable mesogenic moieties, which turn from a rodlike to a kinked shape upon ultraviolet (uv) irradiation, was studied. Depending on the proportion and positional role of the photosensitive groups in the crosslinked polymer network, different types and magnitudes of response were found. The principle consequence of such photoisomerization is the destabilization of the nematic phase, whose order parameter depends on temperature in a near-critical fashion. Accordingly, the effect of uv irradiation is dramatically enhanced near the critical temperature, with the associated reduction in the nematic order parameter manifesting as a change in the macroscopic shape of the elastomer samples, producing a large uniaxial contraction. Theoretical analysis of this phenomenon gives a good quantitative agreement with experiment.
Authors: P. M. Hogan, A. R. Tajbakhsh, E. M. Terentjev
Institution: University of Cambridge
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1982567703